自定义View实现刻度盘

最新推荐文章于 2023-11-01 10:18:17 发布

flying_fish_wj

最新推荐文章于 2023-11-01 10:18:17 发布

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分类专栏： android

本文链接：https://blog.youkuaiyun.com/flying_fish_wj/article/details/54845429

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本文详细介绍了如何在Android平台上通过自定义View来实现一个功能丰富的刻度盘组件，涵盖了布局设计、绘制逻辑及交互实现等方面的关键技术。

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public class ViewTest extends View {

    private Paint mPaint;

    private int mPadding;
    private int mRadius;
    private int mInnerRadius;
    private static int KeDu_Circle = 8;
    public ViewTest(Context context) {
        this(context,null);
    }

    public ViewTest(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public ViewTest(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

    }
    /*
    * 初始化画笔
    * */
    private void init(){
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setDither(true);
        mPadding = getPaddingLeft();
        mRadius = (getWidth() - 2*mPadding)/2;
    }


    /*
    * 绘制圆环
    * */
    private void drawOval(Canvas canvas){
        mPaint.setColor(Color.BLUE);
        canvas.drawCircle(0,0,mRadius,mPaint);
        //内边圆的半径
        mPaint.setColor(Color.WHITE);
       mInnerRadius = mRadius - 50;
        canvas.drawCircle(0,0,mInnerRadius,mPaint);
    }
    /*
    * 绘制刻度
    *
    * */
    private void drawKeDu(Canvas canvas){
        mPaint.setColor(Color.RED);
        for (int i = 1; i <=12;i++) {
            float dx = (float) ((mInnerRadius - 30) * Math.sin(Math.PI/6 * i));
            float dy = (float) ((mInnerRadius - 30)* Math.cos(Math.PI/6 * i));
            canvas.drawCircle(dx,dy,30,mPaint);
        }
    }
    /*
    * 画文本
    * */
    private void drawText(Canvas canvas){
        mPaint.setColor(Color.GREEN);
        mPaint.setTextSize(40);
        for (int i = 1; i <=12;i++) {
            float dy = (float) ((mInnerRadius - 80) * (Math.sin(-Math.PI/ 2 + Math.PI/6* i)));
            float dx = (float) ((mInnerRadius - 80)* (Math.cos(-Math.PI/2 + Math.PI/6*i)));
            Rect textBound = new Rect();
            String s = String.valueOf(i);
            mPaint.getTextBounds(s,0,s.length(),textBound);
            int x = (int) (dx - (textBound.right - textBound.left)/2);
            int y = (int) (dy + (textBound.bottom - textBound.top)/2);
            canvas.drawText(s,x,y,mPaint);
        }

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);
        int minDimension = Math.min(width, height);
        Log.d("wwj", "width is" + width + "height is " + height+"minDimension is "+ minDimension);
        setMeasuredDimension(minDimension,minDimension);
        init();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.save();
        // 将canvas的坐标原点移动到中心位置
        canvas.translate(getWidth()/2,getHeight()/2);
        drawOval(canvas);
        drawKeDu(canvas);
        drawText(canvas);
        canvas.restore();

    }
}